Makes me smile too. Around 2008 while I was at Yahoo! I built a standalone library called Dhaka (literally stuck a pin in a map and used the place name as the project name) that did almost exactly this. It was used on a few of the EU sites but I left before I got chance to open source it. The problem I was trying to solve was eliminating a bunch of duplicate JavaScript that was essentially sending/fetching data to/from a remote source and inserting/replacing it into the current page.